The cause of an apartment house fire that killed six people on November 1st has been ruled accidental. The State Fire Marshal's office says carelessly disposed of smoking materials likely sparked the deadliest blaze in Maine in 40 years.

The smoking materials were deposited in a tall, hollow plastic tube - the kind often found outside public buildings to collect cigarettes. The problem with those, according to the Fire Marshal's office is that if they're not emptied on a regular basis, the debris in the bottom can ignite and cause a fire. When the fire gets going, it melts the plastic. Then, when someone opened the front door of the house, it just blew the fire inside.

Five people didn't escape the building and were killed. According to the Portland Press Herald, a back stairway in the burning half of the duplex was blocked by a bookcase, forcing occupants to jump from a second story window. One of those victims was badly burned and died from his injuries a few days later. Occupants said they don't recall hearing any smoke detectors going off that night.

One victim's widow has filed a wrongful death lawsuit against owner, Gregory Nisbet, however no criminal charges have been brought against him. Another of his properties was inspected in December after complaints of fire hazards. He was given until Tuesday to correct the problems or face sanctions from the city.